Mechanical and fatigue properties of laser additive manufactured Hastelloy X – A Concise review

• Reviews LPBF of Hastelloy X with focus on microstructure, mechanical and fatigue properties. • Identifies how process parameters influence defects, grain structure, and tertiary phase evolution. • Discusses knowledge gaps in fatigue data and modelling under extreme service conditions. • Proposes AI-driven modelling and digital twins for predictive performance design. • Provides a critical synthesis to guide research and industrial use of LPBF Hastelloy X. Hastelloy-X has recently gained significant attention in additive manufacturing (AM) as it is increasingly considered for high-performance applications in the aerospace and energy sectors, thanks to its excellent high-temperature oxidation and corrosion resistance. However, its mechanical behaviour, particularly fatigue performance in AM-processed forms, remains underexplored. This short review consolidates existing studies on the mechanical and fatigue properties of Laser AM Hastelloy-X, covering high-cycle fatigue (HCF), low-cycle fatigue (LCF), and performance at higher temperatures. The influence of microstructural heterogeneity, residual stress, and post-processing strategies on these properties is critically examined. Finally, future research directions are proposed to guide the development of robust design and processing strategies that enhance the fatigue resistance of AM Hastelloy X components.